The functionality of computer blades, such as advanced telecommunications computing architecture (ATCA or Advanced TCA) blades, may be increased through the addition of modules which may be electrically and mechanically coupled to the computer blade. Modules which may be used to expand the functionality of the Advanced TCA blades may include various cards, such as mezzanine cards. The cards may include components such as processors, communications interface, mass storage, etc. One particular variety of mezzanine cards that may be used to expand the functionality of computer blades is advanced mezzanine card (AdvancedMC) modules. In addition to providing components for expanding the functionality of a computer blade, AdvancedMC modules may offer the further benefit of being hot-swappable, allowing the modules to be installed, remove, exchanged, etc., without powering down or removing the computer blade from service. In part, the hot-swappability of AdvancedMC modules utilizes an edge connector allowing sliding engagement between the module and the computer blade.
While modules may be useful for expanding the functionality of a computer blade, they may also create challenges for thermal management. Many components which may be included on a module, for example integrated circuits such as processors, may generate heat which must be dissipated. This challenge is especially prevalent in mezzanine cards that are oriented parallel to the computer blade. Heat generating components extending from the module toward the computer blade may restrict the airflow in between the module and the computer blade. The restricted airflow between the module and the computer blade may decrease the convective cooling capacity. Furthermore, limitations on the spacing between the module and the computer blade may restrict the options for thermal solutions, such as heat spreaders and heatsinks, in connection with heat generating components on the module. Also, in the case of hot-swappable modules, such as advanced mezzanine cards, the hot-swappability of the module may prevent hard mounting of the module to a thermal solution associated with the computer blade.
Difficulties dissipating heat from modules may be compounded for a computer blade including more than one module. Airflow moving over the modules may be progressively heated as it passes over the modules such that the temperature of the airflow may be increased, resulting in a higher downstream temperature. The higher downstream temperature may result in less efficient cooling of downstream modules or components as compared to upstream modules. Therefore, even aside from restriction on airflow, the temperature gradient of the airflow may limit the ability to adequately cool downstream modules. This may limit the overall power which may be dissipated by the modules as a group and/or may restrict the placement of modules on the computer blade, requiring the highest heat generating modules to be placed in an upstream position.